Enhancing thermo-hydraulic performance in flow boiling with hybrid nanofluids in double-layered wavy microchannel heat sink

Abstract

This study uses water-based nanofluids to investigate the thermo-hydraulic performance of flow boiling in single-layer and double-layer wavy microchannels. A numerical analysis employing the Volume of Fluid-Discrete Phase Model (VOF-DPM) evaluates mono nanofluids (Al₂O₃, MWCNT, CuO, SiO₂, TiO₂) and hybrid nanofluids (MWCNT-TiO₂, Al₂O₃-CuO, SiO₂-CuO, MWCNT-Al₂O₃, SiO₂-TiO₂) across varying concentrations. Results identify 2 % nanoparticle concentration as optimal, with performance degradation at higher levels due to increased viscosity and nanoparticle agglomeration. MWCNT and MWCNT-TiO₂ hybrid nanofluids demonstrate superior heat transfer performance among the tested fluids. The double-layer microchannel configuration significantly enhances heat transfer, reduces hotspots, and ensures uniform heat distribution compared to single-layer designs. An optimal MWCNT: TiO₂ ratio of 1.5:0.5 achieves the highest Nusselt number and performance factor, leveraging the thermal conductivity of MWCNT and the wettability of TiO₂. Geometric parameters such as wavelength and amplitude further influence performance, with larger wavelengths and moderate amplitudes striking a balance between heat transfer and frictional losses. This work establishes double-layer wavy microchannels with MWCNT-TiO₂ hybrid nanofluids as a promising solution for advanced thermal management applications.